Orbital’s Minotaur I successfully lofts multitude of payloads

November 19, 2013 by William Graham

Orbital Sciences Corporation have launched the ORS-3 mission for the US military, using a Minotaur I rocket to demonstrate technology aimed at reducing costs for future missions. The rocket lofted a record 29 satellites, as well as two attached payloads, from the Mid-Atlantic Regional Spaceport on Wallops Island at 20:15 local time Tuesday (01:15 UTC on Wednesday).

Minotaur I Launch:

The primary goal of the ORS-3 mission is to test new procedures and equipment which would allow future missions to be flown at lower cost and with faster response times.

The primary experiment is the Autonomous Flight Safety System (AFSS) which will be used to monitor the trajectory of the rocket during its ascent to orbit to ensure the vehicle does not go off-course; enabling the rocket to activate its own flight termination system should it become necessary.

It is hoped that an autonomous system would reduce the level of monitoring required from range safety assets on the ground.

Once the Minotaur reached orbit, AFSS will have completed its mission. A second experiment is also attached to the Minotaur’s upper stage: SoM/DoM is a passive device intended to hasten the upper stage’s decay from orbit.

Developed by MMA Design of Colorado, SoM/DoM is based on that company’s Dragnet design. It will be one of the first two Dragnet prototypes to fly, the other being installed aboard one of the satellites which the Minotaur is deploying.

Twenty nine separable payloads flew aboard the Minotaur. These consisted of one small satellite, STPSat-3, and twenty eight CubeSats mounted in sixteen PPOD deployers. The totals of thirty one payloads and twenty nine separable payloads are both new records for the most spacecraft launched by, and deployed by, a single rocket.

Multiple-satellite launches are nothing new. In April 1959 Vanguard SLV-5 lifted off from Cape Canaveral carrying an unnamed magnetospheric research satellite. Also aboard the rocket was a small package designed to inflate into a 76-centimetre (30 inch) balloon in orbit.

Although this first attempt to use the same rocket to orbit more than one satellite failed – recontact between the first and second stages put paid to the launch attempt – the concept has been used ever since.

The first successful multi-satellite launch was conducted almost exactly a year after the failed Vanguard launch, when a Thor DM-21 Ablestar placed the Transit 1B spacecraft into orbit.

The secondary payload was an inert mockup of a Solrad radiation research and signals intelligence satellite, intended to demonstrate the concept of dual-payload launches for future Solrad missions. Two months later Solrad 1 was launched as a secondary payload on another Thor DM-21 Ablestar, as it placed Transit 2A into orbit.

The record for most satellites launched by a single rocket is currently held by the Russo-Ukrainian Dnepr, which placed fourteen satellites into low Earth orbit in April 2007. An eighteen-satellite launch was attempted in 2006, also by a Dnepr, however it failed to achieve orbit.

These figures do not include the two Atlas-Agena launches in 1961 and 1963 which each deployed a little under half a billion copper dipoles as part of Project Westford, a communications experiment conducted by the Massachusetts Institute of Technology’s Lincoln Laboratory.

Two Soviet Tsyklon-3 launches with Koltso satellites are also discounted – on these missions the satellites, designated Kosmos 1985 and Kosmos 2052, each released 36 radar calibration spheres, or Rombs. A third Koltso, Kosmos 2106, was launched in 1990 but did not deploy its full complement of spheres.

Although the ORS-1 mission is expected to set a new record for most functional payloads on a single rocket, this record is unlikely to stand for long. Nine thousand kilometres from Wallops Island, at the Dombarovsky missile base in Russia’s Orenburg Oblast region, a Dnepr is being prepared for a launch which will carry 33 payloads into orbit. That mission is scheduled to launch on Thursday morning, less than 32 hours after the Minotaur lifts off.

The largest spacecraft aboard the Minotaur, STPSat-3 was built by Ball Aerospace and is based on the Ball Configurable Platform (BCP) 100.

It is similar to the STPSat-2 spacecraft, USA-217, which was launched by a Minotaur IV in 2010, however it carries a different array of experiments. STPSat-3 has a mass of 180 kilograms (400 lb), and a design life of one year.

STPSat-3 will be operated by the United States Air Force as part of the Space Test Program. It has five instruments. The Integrated Miniaturized Electrostatic Analyzer Reflight (iMESA-R) is an experiment designed by the US Air Force Academy. Following up from research conducted by the Cerberus instrument flown to the International Space Station aboard STS-134, iMESA-R will be used for plasma research.

The Small Wind and Temperature Spectrometer (SWATS), and instrument which was developed by the Naval Research Laboratory, will also be used to research plasma in the thermosphere and ionosphere.

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The Total Solar Irradiance Calibration Transfer Experiment (TCTE), which was developed by the University of Colorado’s Laboratory for Atmospheric and Space Physics and will be operated by NASA and the National Oceanic and Atmospheric Administration (NOAA), will be used to study the amount of energy from the sun which reaches the Earth’s atmosphere.

Solar irradiance data is currently provided by NASA’s SORCE satellite, which is long past the end of its design life.

The Glory satellite was to have continued data collection; however it was lost in a launch failure in 2011. TCTE will serve as a gapfiller until the launch of the first JPSS Free-Flyer satellite in 2017, however by this time STPSat-3 will have been in orbit for over four times its design life.

STPSat-3’s other two payloads are technology demonstration experiments. Joint Component Research, or J-CORE, is an experiment for the Space and Missile Defence Command (SMDC), Air Force Research Laboratory and Electro-Optical Countermeasures Branch to study how components react to phenomena in the space environment. The Strip Sensor Unit, or SSU, is a prototype sensor assembly for the Air Force Research Laboratory.

Twenty-eight other satellites joined STPSat-3 for its ride into orbit. Eleven of these CubeSats werelaunched as part of NASA’s Educational Launch of Nanosatellites, or ELaNa, programme. Designated ELaNa IV, it is the fourth launch of the programme, which aims to provide access to space for CubeSats built and operated by educational institutions, mostly universities.

CubeSats are small satellites built to a set of standard sizes. A single-unit CubeSat is cubic in shape, measuring ten centimetres (3.9 inches) along all edges. Double and triple CubeSats retain the same cross-section, but have lengths of 20 and 30 centimetres respectively.

CubeSats’ length can also vary in half-units; several 1.5 unit CubeSats, with length of fifteen centimetres, have already been launched. Several six-unit CubeSats are under construction, which measure 10 by 20 by 30 centimetres.

The first six CubeSats to be launched; AAU-CubeSat 1, CanX-1, CUTE-1, DTUSat, QuakeSat and XI-IV, were successfully deployed during a test flight of Russia’s Rokot launcher in June 2003. Since then the numbers being launched have increased year-by-year. As of the start of November, 21 have already been placed into orbit this year alone.

With more and more universities developing CubeSats, NASA began the ELaNa programme to enable excess capacity on launches to be used for these missions. The first ELaNa launch occurred in 2011, with three CubeSats flying as secondary payloads on a Taurus-XL rocket with NASA’s Glory climate research satellite. All four satellites were lost when the rocket failed to achieve orbit.

The ELaNa III and VI missions, launched by Delta II and Atlas V rockets in October 2011 and September 2012 respectively, were both launched successfully. The next launch, ELaNa III, is scheduled for early December when an Atlas V orbits the NROL-39 spacecraft for the National Reconnaissance Office.

The CubeSats aboard the ORS-3 mission will be deployed using two different types of deployers; eight Poly Picosatellite Orbital Deployers (PPODs), which accommodate the equivalent of three one-unit satellites each, and four larger dispensers each with twice the capacity of a PPOD. The dispensers provide a total of 48 CubeSat units of capacity – or a combined volume of 48 cubic decimetres (litres – or 1.70 cubic feet).

Cajun Advanced Picosatellite Experiment 2, or CAPE-2, will be operated by the University of Louisiana. A single-unit CubeSat, it is the second CAPE satellite developed by the university. CAPE-1 was launched in 2007 – coincidentally aboard the Dnepr mission which set the current record for the most satellites deployed by one rocket.

CAPE-2 will conduct communications technology experiments as well as demonstrating deployable solar panels and will also be used for outreach. CAPE-2 is launching in slot C of PPOD number 5.

ChargerSat-1, or ChargerSat-1.2, is in slot C of PPOD 7. Another single-unit spacecraft, it will be operated by the University of Alabama at Huntsville. With a mass of one kilogram, it will conduct technology demonstration experiments aimed at enhancing communications and power generation systems for future CubeSat missions. It will also demonstrate a gravity-gradient stabilisation system, using a boom deployed from the nadir of the spacecraft.

ChargerSat-1.0 was an unflown prototype, while ChargerSat-1.1 was used for parts of the testing programme and now serves as a ground spare.

Close Orbiting Propellant Plume and Elemental Recognition, or COPPER, also known as SLU-01, is a single-unit satellite for Saint Louis University. Designed for the University Nanosatellite Program, it lost out to Oculus-ASR for funding under the Nanosat-6 competition.

The satellite will conduct infrared imagery and host a technology demonstration payload for SLU’s next CubeSat, Argus, which is scheduled to launch next year on the maiden flight of the SPARK rocket. For launch, COPPER will be in slot A of PPOD 7.

DragonSat-1, which is contained within slot A of PPOD 6, is a one-unit CubeSat to be operated by Drexel University of Philadelphia in collaboration with the US Naval Academy. Its primary objective is to provide optical imagery of the earth’s aurorae; it will also be used to demonstrate gravity-gradient stabilisation techniques.

Ho’oponopono-2 is a three-unit CubeSat which will be operated by the University of Hawaii. Built in conjunction with the US Air Force, the satellite is gravity-gradient-stabilised, and carries a GPS receiver and a C-band transponder. It will be used to help calibrate radar tracking stations used to monitor spacecraft, and will also serve as a technology demonstrator for the Ho’oponopono-3 satellite, which will replace it.

Ho’oponopono-2 has a mass of 3.5 kilograms and is expected to operate for at least a year. The satellite occupies the whole of PPOD 2.

KySat-2 is a reflight of the KySat-1 spacecraft lost in the failed ELaNa I launch in 2011. Operated by Kentucky Space, it will be used for educational outreach. A single-unit CubeSat, it occupied slot A of PPOD 5. The satellite carries a technology demonstration experiment termed a “stellar gyroscope” which will test a new method of determining the spacecraft’s attitude.

TJ3Sat, the Thomas Jefferson CubeSat, which is also geared towards educational outreach, rode in slot B of PPOD 3. Another one-unit spacecraft, TJ3Sat is being flown for Thomas Jefferson High School, making it the first satellite to be built and operated by a US High School.

The spacecraft is based on a Pumpkin CubeSat kit, and has been supported by Stensat and Orbital Sciences Corporation. TJ3Sat carries a text-to-speech synthesiser, allowing it to transmit messages which are uplinked as text.

Trailblazer, or SPA-1, will be operated by the University of New Mexico. It is another single-unit CubeSat based on a Pumpkin Incorporated kit, which will be used to demonstrate the Space Plug-and-Play Architecture (SPA) concept for the US Air Force Laboratory, which is aimed at reducing the time taken to develop new satellites. Trailblazer will ride to orbit in slot C of PPOD 6.

SwampSat, for the University of Florida, will demonstrate miniaturised gyroscope systems for future CubeSat missions. A single-unit satellite, was located in slot B of PPOD 7.

The Vermont Lunar CubeSat is a one-unit satellite for the Vermont Technical College aimed at demonstrating technologies which will be used in the future to land a CubeSat on the moon. The satellite also carries light emitting diodes which will be visible from to observers on the ground with the aid of binoculars. It was in slot A of PPOD 3.

While not strictly part of the ELaNa programme, PhoneSat-2.4 is included with the ELaNa IV CubeSats. The fourth satellite to be launched as part of NASA’s PhoneSat programme, investigating the use of off-the-shelf mobile phone components to operate satellites, it follows on from the Alexander, Graham and Bell CubeSats launched aboard the first Antares launch earlier this year. All three of those satellites have since decayed from orbit.

PhoneSat-2.4 is a PhoneSat-2 spacecraft, based around a Google Nexus-S smartphone with version 2.3.3 of the Android operating system.

It is a single-unit CubeSat with a mass of approximately one kilogram, built and operated by NASA’s Ames Research Center. The satellite was deployed from slot B of deployer 6.

The US Military Academy’s Black Knight 1 was initially reported to be an ELaNa payload on the launch, and is part of the ELaNa programme; however it is not included in the list of satellites on the ELaNa IV mission published by NASA.

It is likely that it is being flown as an Air Force payload rather than a NASA payload, however it is probably still aboard the Minotaur. Black Knight 1 is a single-unit satellite produced by cadets at the West Point barracks. A technology demonstration spacecraft, it is based on a CubeSat kit purchased from Pumpkin Incorporated. It is likely in slot C of PPOD 3; however this has not been confirmed.

Firefly is a three-unit CubeSat mission, a joint project between NASA’s Goddard Space Flight Center and the National Science Foundation. The satellite will be used to investigate whether lightning is responsible for events known as Terrestrial Gamma-Ray Flashes, or TGFs – the emission of gamma photons from sources in the Earth’s atmosphere.

The Naval Postgraduate School Solar Cell Array Tester, or NPS-SCAT, was developed by the Naval Postgraduate School and will be operated in conjunction with the Space Test Program. Its payload is the Solar Cell Measurement System, or SMS, which was originally intended to be flown aboard the NPSat-1 satellite.

Scheduled for launch aboard an Atlas V in 2007 as part of the STP-1 mission, NPSat-1 was removed from the Atlas launch after it fell behind schedule, and since appears to have been cancelled. NPS-SCAT is a three-unit CubeSat which will be used to characterise the degradation of solar cells over time in orbit. NPS-SCAT rode to orbit along with the ELaNa payloads, in slot B of PPOD 5.

Three ORS CubeSats are part of the payload. The ORS Enabler Satellite, ORSES, is a communications satellite similar in design to the US Army’s SMDC-ONE satellites. It is a three-unit CubeSat, equipped with Vulcan and Gryphon encrypted communications systems. The ORS-Tech 1 and 2 spacecraft are also three-unit vehicles, developed by Johns Hopkins University. Their missions have not been confirmed.

Four Prometheus satellites, which are believed to be operated by the Special Operations Command, are included in the payload. Each is a 1.5 unit CubeSat. According to some reports there may be eight Prometheus spacecraft rather than four.

SENSE 1 and 2 are a pair of three-unit CubeSats built by the US Air Force to demonstrate procedures for developing and launching satellites rapidly and at lower cost. The spacecraft are equipped with electron density sensors to conduct ionospheric research and study the occultation of radio signals due to electrons in the environment of the spacecraft.

STARE-B, or Horus, is the second satellite to be launched as part of the Space-Based Telescopes for Actionable Refinement of Ephemeris, or STARE, programme being conducted by the Lawrence Livermore National Laboratory. A three-unit CubeSat, it will be used to demonstrate the optical tracking of space debris. It follows on from the STARE-A, or Re, satellite launched with NROL-36 last year.

The identity of the remaining four CubeSats – which occupy six units of space – or two PPODs – was not confirmed. Several other ELaNa payloads, including TetherSat, a technology experiment utilising a pair of 1.5-unit CubeSats joined by a tether – have been linked to the flight but are not included in the ELaNa IV press kit, which suggests they are not present.

Others have speculated that the four Prometheus satellites may in reality be four pairs of satellites, for a total of eight spacecraft. The latter seems more likely, however the exact compliment of satellites aboard the rocket will probably not become clear for some time.

The ORS-3 launch was performed by Orbital Sciences Corporation, using a Minotaur I rocket. It was the eleventh flight of the Minotaur I, a derivative of the Minuteman missile which first flew in 2000, and the twenty-fifth overall launch of a Minotaur rocket.

Orbital’s Minotaur family consists of rockets converted from retired intercontinental ballistic missiles, with the Minotaur I and II being based on the Minuteman, while the larger Minotaur III, IV, V and VI are derived from the Peacekeeper missile.

The Minotaur II is used for suborbital launches, mostly as targets for missile defence tests and experiments, while the Minotaur III is also designed for suborbital applications but is yet to fly. The Minotaur I and V are used for orbital launches, while the Minotaur IV has been used for both suborbital and orbital missions. The Minotaur VI, which is designed for launches to higher orbits, has not yet been launched.

It is unclear if and when the Minotaur I will next fly. No further launches have been confirmed; however Orbital has not announced plans to retire the rocket. Due to regulations relating to the use of retired missile stages, the Minotaur I can only be used to orbit US military payloads unless special authorisation is granted – such as that given for the Minotaur V launch of LADEE earlier this year.

Orbital’s other small rockets, Pegasus and Taurus, are in the same position as the Minotaur I, with no concrete launches on their manifest, although NASA’s CYGNSS spacecraft are likely to launch on a Pegasus in 2016, and 2017’s launch of TESS has also been linked with the air-launched rocket.

The Minotaur’s mission to deploy the ORS-3 payloads lasted 30 minutes and 44.06 seconds from liftoff to the completion of upper stage safing.

When the countdown reaches zero, the Minotaur’s first stage ignited and the rocket immediately rose from the pad. Two and a half seconds into the flight the rocket began its pitchover. The rocket passed through max-q, the point of the flight at which dynamic pressure on the vehicle was at its greatest, 37.2 seconds after liftoff.

Upon first stage burnout, approximately 61.4 seconds after liftoff, the spent stage was jettisoned and the second stage ignited more or less instantaneously. Sixteen and a half seconds later the interstage, or “skirt”, was jettisoned from the aft end of the second stage.

Second stage flight lasted for 72 seconds, before the stage burned out and separated. The third stage lit 2.1 seconds after separation, beginning a 74.1-second burn. At an altitude of around 139 kilometres (86.4 miles), about ten seconds into the third stage burn, the payload fairing separated from the nose of the rocket.

Following third stage burnout, the mission entered a coast phase as the rocket climbed to its apogee of a little over 500 kilometres (310 miles).

Five minutes and 27.3 seconds into the coast, the spent third stage was jettisoned. Powered flight resumed with stage four ignition eleven seconds later. The fourth stage made a 66.1-second burn to insert the payloads into their final orbit.

Twelve minutes and 14.1 seconds after liftoff, just under two minutes after fourth stage burnout, STPSat-3 separated from the rocket.

Eight seconds after STPSat-3 separated, the payload deployment sequencer, responsible for dispensing the CubeSats, was commanded to start. Before separation occurred, however, the upper stage used its reaction control system to perform a collision avoidance manoeuvre. This was scheduled for 152 seconds after STPSat-3’s separation.

The first tranche of CubeSats were released 19 minutes and 49 seconds after launch, with the remainder separating two and a half minutes later.

A second collision avoidance manoeuvre was performed three minutes and 35 seconds after the second CubeSat deployment event. The reaction control system was burned again to deplete any remaining fuel supply, 190 seconds later, with the end of mission being declared around 100 seconds afterwards.

The target orbit for this mission is approximately circular, at around 500 kilometres altitude with an inclination of 40.5 degrees.

Launch Pad 0B at the Mid-Atlantic Regional Spaceport was the point of departure for the ORS-3 mission. A multi-purpose launch complex which has also been used by Orbital’s Minotaur V and Alliant Techsystems ALV-X1 rocket, LP-0B was built in the early 2000s as part of the development of a commercial launch site on Wallops Island. The first launch from the complex occurred in December 2006 with a Minotaur I orbiting TacSat-2.